Ensure latest version from VersionMap contains...

...all structures at their current versions.

This commit also bumps the crate verion to 0.1.2

Signed-off-by: Ioana Chirca <[email protected]>

CHANGELOG.md

@@ -1,3 +1,8 @@
+# v0.1.2
+
+- Added a safety check for enforcing that the VersionMaps provided for
+    (de)serialization are up-to-date with the latest versions of the structs.
+
 # v0.1.1
 
 - Removed "versionize" dependency.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "versionize_derive"
-version = "0.1.1"
+version = "0.1.2"
 license = "Apache-2.0"
 authors = ["Amazon Firecracker team <[email protected]>"]
 description = "Implements the Versionize derive proc macro."

src/descriptors/struct_desc.rs

@@ -3,7 +3,7 @@
 
 use common::{Descriptor, GenericDescriptor};
 use fields::struct_field::*;
-use helpers::compute_version;
+use helpers::{compute_version, latest_version_check};
 use quote::{format_ident, quote};
 
 pub(crate) type StructDescriptor = GenericDescriptor<StructField>;
@@ -71,13 +71,16 @@ impl Descriptor for StructDescriptor {
 
         // Generate code to map the app version to struct version and wrap the
         // deserializers with the `version` match.
-        quote! {
-            let version = version_map.get_type_version(app_version, <Self as Versionize>::type_id());
+        let mut deserializer = proc_macro2::TokenStream::new();
+        deserializer.extend(latest_version_check(self.version()));
+        deserializer.extend(quote! {
             match version {
                 #versioned_deserializers
                 _ => panic!("Unknown {:?} version {}.", <Self as Versionize>::type_id(), version)
             }
-        }
+        });
+
+        deserializer
     }
 
     fn version(&self) -> u16 {

src/descriptors/union_desc.rs

@@ -3,7 +3,7 @@
 
 use common::{Descriptor, Exists, FieldType, GenericDescriptor};
 use fields::union_field::*;
-use helpers::compute_version;
+use helpers::{compute_version, latest_version_check};
 use quote::quote;
 
 pub(crate) type UnionDescriptor = GenericDescriptor<UnionField>;
@@ -40,13 +40,16 @@ impl Descriptor for UnionDescriptor {
             });
         }
 
-        quote! {
-            let version = version_map.get_type_version(app_version, Self::type_id());
+        let mut deserializer = proc_macro2::TokenStream::new();
+        deserializer.extend(latest_version_check(self.version()));
+        deserializer.extend(quote! {
             match version {
                 #versioned_deserializers
-                _ => panic!("Unknown {:?} version {}.", Self::type_id(), version)
+                _ => panic!("Unknown {:?} version {}.", <Self as Versionize>::type_id(), version)
             }
-        }
+        });
+
+        deserializer
     }
 
     fn version(&self) -> u16 {

src/helpers.rs

@@ -3,7 +3,7 @@
 
 use super::{ATTRIBUTE_NAME, END_VERSION, START_VERSION};
 use common::Exists;
-use quote::format_ident;
+use quote::{format_ident, quote};
 use std::cmp::max;
 use std::collections::hash_map::HashMap;
 
@@ -79,6 +79,17 @@ pub fn is_array(ty: &syn::Type) -> bool {
     }
 }
 
+// Enforce that the latest VersionMap version is up-to-date with the latest struct version.
+pub(crate) fn latest_version_check(current_version: u16) -> proc_macro2::TokenStream {
+    quote! {
+        // Get the struct version for the input app_version.
+        let version = version_map.get_type_version(app_version, <Self as Versionize>::type_id());
+        if app_version == version_map.latest_version() && version != #current_version {
+            return Err(VersionizeError::VersionMapNotUpdated);
+        }
+    }
+}
+
 // Compute current struct version by finding the latest field change version.
 pub(crate) fn compute_version<T>(fields: &[T]) -> u16
 where

src/lib.rs

@@ -19,6 +19,7 @@ use common::Descriptor;
 use descriptors::{
     enum_desc::EnumDescriptor, struct_desc::StructDescriptor, union_desc::UnionDescriptor,
 };
+use helpers::latest_version_check;
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{parse_macro_input, DeriveInput};
@@ -50,16 +51,18 @@ pub fn impl_versionize(input: TokenStream) -> proc_macro::TokenStream {
     let version = descriptor.version();
     let versioned_serializer = descriptor.generate_serializer();
     let deserializer = descriptor.generate_deserializer();
-    let serializer = quote! {
-        // Get the struct version for the input app_version.
-        let version = version_map.get_type_version(app_version, <Self as Versionize>::type_id());
+
+    let mut serializer = proc_macro2::TokenStream::new();
+    serializer.extend(latest_version_check(version));
+    serializer.extend(quote! {
         // We will use this copy to perform semantic serialization.
         let mut copy_of_self = self.clone();
         match version {
             #versioned_serializer
             _ => panic!("Unknown {:?} version {}.", &<Self as Versionize>::type_id(), version)
         }
-    };
+    });
+
     (quote! {
         impl Versionize for #ident #generics {
             fn serialize<W: std::io::Write>(&self, writer: &mut W, version_map: &VersionMap, app_version: u16) -> VersionizeResult<()> {